I. Field
The present disclosure relates generally to communication, and more specifically to techniques for operating a wireless terminal.
II. Background
Wireless communication networks are widely deployed to provide various communication services such as voice, data, video, broadcast, messaging, etc. These networks include multiple-access radio networks capable of supporting communication for multiple users by sharing the available radio resources. Examples of such radio networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, and Orthogonal FDMA (OFDMA) networks. A CDMA network may implement a radio technology such as cdma2000, Wideband-CDMA (W-CDMA), etc. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). These various radio technologies and standards are known in the art.
Some radio networks can support voice and data services. One such radio network is a CDMA2000 1X network that implements IS-2000 and/or IS-95. A CDMA2000 1X network is also referred to as a 1X network, a CDMA network, etc. Voice and data services have different characteristics and requirements. For example, voice service typically requires a common grade of service (GoS) for all users and further imposes relatively stringent delay requirements. In contrast, data service may be able to tolerate different GoS for different users and variable delays. To support both voice and data services, the 1X network may first allocate radio resources to voice users and then allocate any remaining radio resources to data users who are able to tolerate longer delays.
Some radio networks are optimized for data service. One such radio network is a High Rate Packet Data (HRPD) network that implements IS-856. An HRPD network is also referred to as a CDMA2000 1xEV-DO network, a 1xEV-DO network, a 1x-DO network, an HDR network, etc. A data session typically has long periods of silence and sporadic bursts of traffic. The HRPD network allocates most or all of the radio resources to one user at any given moment, thereby greatly increasing the peak data rate for the user being served.
A service provider/network operator may deploy multiple radio networks to provide enhanced services for its subscribers. For example, the service provider may deploy a 1X network to support voice and data services for a large geographic area and may deploy an HRPD network to support data service for areas where data usage is expected to be high. The coverage areas of the two radio networks typically overlap. A terminal may be under the coverage of only the 1X network, or only the HRPD network, or both 1X and HRPD networks at any given moment. The terminal may be able to receive different services depending on its location and other factors.